665222666 has 4 divisors (see below), whose sum is σ = 997834002. Its totient is φ = 332611332.

The previous prime is 665222567. The next prime is 665222671. The reversal of 665222666 is 666222566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666222566 = 2 ⋅333111283.

It can be written as a sum of positive squares in only one way, i.e., 493062025 + 172160641 = 22205^2 + 13121^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166305665 + ... + 166305668.

Almost surely, 2^665222666 is an apocalyptic number.

665222666 is a deficient number, since it is larger than the sum of its proper divisors (332611336).

665222666 is a wasteful number, since it uses less digits than its factorization.

665222666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332611335.

The product of its digits is 311040, while the sum is 41.

The square root of 665222666 is about 25791.9108636797. The cubic root of 665222666 is about 872.9492834169.

The spelling of 665222666 in words is "six hundred sixty-five million, two hundred twenty-two thousand, six hundred sixty-six".